WO2022137571A1

WO2022137571A1 - Authentication device, authentication method, and authentication program

Info

Publication number: WO2022137571A1
Application number: PCT/JP2020/048990
Authority: WO
Inventors: 俊日夏
Original assignee: 三菱電機株式会社
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2022-06-30
Also published as: DE112020007726T5; JPWO2022137571A1; CN116601627A; US20230259599A1; JP6983365B1

Abstract

This signal acquisition unit (21) acquires a biological signal. An authentication information generation unit (22) generates, from the biological signal acquired by the signal acquisition unit (21), authentication information that differs in accordance with the entity of a living organism. A region information generation unit (23) generates, from the biological signal acquired by the signal acquisition unit (21), region information that differs, even with the same entity, in accordance with the acquired region of the biological signal. An authentication unit (24) performs authentication on the basis of the authentication information generated by the authentication information generation unit (22) and the region information generated by the region information generation unit (23).

Description

Authentication device, authentication method and authentication program

This disclosure relates to authentication technology using biological signals.

With the development of IoT (Internet of Things), the scenes and devices for authenticating the target person are diversifying. Biometric authentication using physical features that can be measured as an image, such as face authentication or fingerprint authentication, has less burden on the subject than password authentication or the like. Therefore, biometric authentication has become widespread along with devices such as smartphones and smart watches.
As a physical feature, in recent years, attempts have been made to use an electrocardiogram (hereinafter referred to as ECG: Electrocardiogram), which is a biological signal obtained by measuring the electrical activity of the heart, for authentication. In some countries, ECG authentication devices are being put into practical use. Research is also being conducted on the use of photoelectric volume pulse waves (hereinafter, PPG: Photoplethysmogram), which are biological signals obtained by optically measuring the behavior of blood vessels associated with heartbeat, for authentication. Here, ECG and PPG are time series signals.

As described in Non-Patent Documents 1 and 2, biological signals such as ECG and PPG may be measured at various parts of the body. Using this, there is a possibility that a sensor will be installed in a place where the attacker impersonates the target person's body and the biological signal will be measured illegally. Further, since the biological signal is often treated as an electric signal, as described in Non-Patent Document 1, it is conceivable that an attacker illegally generates a biological signal and inputs it to an authentication device.
Therefore, in order for authentication using biological signals to become widespread and diversified in the future, an authentication method equipped with countermeasures against spoofing attacks due to measurement of illegal biological signals and generation of illegal biological signals will be required.

Patent Document 1 and Non-Patent Document 3 describe authentication provided with countermeasures against spoofing attacks using information illegally generated by an attacker.
Patent Document 1 guarantees that the presented fingerprint was obtained from a living body (finger) rather than artificially generated by confirming that PPG can be measured from a finger before performing fingerprint authentication. It is described that the authentication is performed.
In Non-Patent Document 3, by confirming that PPG can be measured by a camera and image processing at the same time as face recognition, the object measured by the camera for face recognition is not an artificial object such as a mask but a living body (face). It is stated that the certification is performed by guaranteeing that.

Japanese Unexamined Patent Publication No. 2020-093114

The spoofing attack countermeasures described in Patent Document 1 and Non-Patent Document 3 are both countermeasures added to authentication based on physical features acquired as images, such as fingerprints or faces. Therefore, countermeasures against spoofing attacks on authentication using biological signals are insufficient. In particular, no countermeasures have been taken from the viewpoint of authentication for spoofing attacks by fraudulent measurement of biological signals against a spoofing partner.
It is an object of the present disclosure to make it feasible to take measures against spoofing attacks due to unauthorized measurement of biological signals.

The authentication device according to this disclosure is
A signal acquisition unit that acquires biological signals,
An authentication information generation unit that generates different authentication information according to an individual living body from the biological signal acquired by the signal acquisition unit.
A site information generation unit that generates different site information from the biological signal depending on the acquisition site of the biological signal.
It includes an authentication unit that performs authentication based on the authentication information generated by the authentication information generation unit and the site information generated by the site information generation unit.

In this disclosure, authentication is performed using site information in addition to authentication information. As a result, it is possible to control so that authentication does not succeed when a biological signal illegally measured in a part other than the intended part is used. Therefore, it is possible to implement countermeasures against spoofing attacks due to unauthorized measurement of biological signals.

The block diagram of the authentication apparatus 10 which concerns on Embodiment 1. FIG. The flowchart of the process of the authentication apparatus 10 which concerns on Embodiment 1. FIG. An explanatory diagram of site information when the biological signal according to the first embodiment is ECG. An explanatory diagram of site information when the biological signal according to the first embodiment is PPG. Explanatory drawing of authentication standard information and site standard information which concerns on Embodiment 1. FIG. The flowchart of the process of the authentication apparatus 10 which concerns on modification 2. The block diagram of the authentication apparatus 10 which concerns on Embodiment 2. FIG. The flowchart of the process of the authentication apparatus 10 which concerns on Embodiment 2. The explanatory view of the composite signal which concerns on Embodiment 2. The flowchart of the process of the authentication apparatus 10 which concerns on modification 5. The block diagram of the authentication apparatus 10 which concerns on Embodiment 3. FIG. The flowchart of the process of the authentication apparatus 10 which concerns on Embodiment 3. Explanatory drawing of authentication standard information and site standard information which concerns on Embodiment 3. Explanatory drawing of authentication standard information and site standard information which concerns on Embodiment 3. The flowchart of the process of the authentication apparatus 10 which concerns on modification 6. The block diagram of the authentication apparatus 10 which concerns on Embodiment 4. FIG. The flowchart of the process of the authentication apparatus 10 which concerns on Embodiment 4. The explanatory view of the physiological index which concerns on Embodiment 4. An explanatory diagram of the authentication standard information, the site standard information, and the reference value of the physiological index according to the fourth embodiment. The flowchart of the process of the authentication apparatus 10 which concerns on modification 7.

Embodiment 1.
*** Explanation of configuration ***
The configuration of the authentication device 10 according to the first embodiment will be described with reference to FIG.
The authentication device 10 is a computer. As a specific example, the authentication device 10 is a wearable such as a smart watch, a mobile device such as a smartphone, and a stationary device installed at an entrance of a building or the like.

The authentication device 10 includes hardware of a processor 11, a memory 12, a sensor interface 13, a display interface 14, a communication interface 15, and an auxiliary storage device 16. The processor 11 is connected to other hardware via a signal line and controls these other hardware.

The processor 11 is an IC (Integrated Circuit) that performs processing. Specific examples of the processor 11 are a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and a GPU (Graphics Processing Unit).

The memory 12 is a storage device that temporarily stores data. As a specific example, the memory 12 is a SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory).

The sensor interface 13 is an interface for communicating with a sensor 31 mounted on the authentication device 10 or installed outside the authentication device 10. As a specific example, the sensor interface 13 is a USB (Universal Serial Bus) port.
In FIG. 1, the sensor 31 is mounted on the authentication device 10, but the sensor 31 may be installed outside the authentication device 10. For example, the sensor 31 may be worn by the subject independently of the authentication device 10. Further, the sensor interface 13 may be provided together with the sensor 31 independently of the authentication device 10. In this case, it is connected to the sensor interface 13 via the communication interface 15.

The display interface 14 is an interface for communicating with a display mounted on the authentication device 10 or installed outside the authentication device 10. As a specific example, the display interface 14 is a port of HDMI (registered trademark, High-Definition Multimedia Interface).

The communication interface 15 is an interface for communicating with an external device. The communication interface 15 is, as a specific example, a port of Ethernet®.

The auxiliary storage device 16 is a storage device for storing data. As a specific example, the auxiliary storage device 16 is an HDD (Hard Disk Drive). The auxiliary storage device 16 includes an SD (registered trademark, Secure Digital) memory card, CF (CompactFlash, registered trademark), a NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, and a DVD (Digital Versaille Disk). ) May be a portable recording medium.

The authentication device 10 includes a signal acquisition unit 21, an authentication information generation unit 22, a site information generation unit 23, and an authentication unit 24 as functional components. The functions of each functional component of the authentication device 10 are realized by software.
The auxiliary storage device 16 stores a program that realizes the functions of each functional component of the authentication device 10. This program is read into the memory 12 by the processor 11 and executed by the processor 11. As a result, the functions of each functional component of the authentication device 10 are realized.

In FIG. 1, only one processor 11 was shown. However, the number of processors 11 may be plural, and the plurality of processors 11 may execute programs that realize each function in cooperation with each other.

*** Explanation of operation ***
The operation of the authentication device 10 according to the first embodiment will be described with reference to FIGS. 2 to 5.
The operation procedure of the authentication device 10 according to the first embodiment corresponds to the authentication method according to the first embodiment. Further, the program that realizes the operation of the authentication device 10 according to the first embodiment corresponds to the authentication program according to the first embodiment.

The processing flow of the authentication apparatus 10 according to the first embodiment will be described with reference to FIG.
(Step S101: Signal acquisition process)
The signal acquisition unit 21 acquires the biological signal of the subject from the sensor 31 connected via the sensor interface 13. Specific examples of the biological signals include time-series signals such as ECG obtained by measuring the electrical activity of the heart and PPG obtained by optically measuring the behavior of blood vessels associated with the heartbeat. However, biological signals are not limited to these. The signal acquisition unit 21 writes the biological signal to the memory 12.

(Step S102: Authentication information generation process)
The authentication information generation unit 22 generates different authentication information according to the individual of the living body from the biological signal acquired in step S101.
Specifically, the authentication information generation unit 22 reads the biological signal from the memory 12. The authentication information generation unit 22 generates authentication information by a method of generating a waveform of a biological signal as authentication information, or extracting a feature amount from the biological signal and using the feature amount as authentication information. As long as the authentication information differs depending on the individual living body, the method of generating the authentication information is not limited. The authentication information generation unit 22 writes the authentication information in the memory 12.

(Step S103: Part information generation process)
The site information generation unit 23 generates different site information from the biological signal acquired in step S101 according to the acquisition site of the biological signal even for the same individual.
Specifically, the site information generation unit 23 reads the biological signal from the memory 12. The site information generation unit 23 generates a waveform of a biological signal as site information, or extracts a feature amount from the biological signal and uses the feature amount as site information, as in the method of generating authentication information. Generate information. However, the site information needs to be different depending on the site where the biological signal is acquired. As long as the site information differs depending on the site where the biological signal is acquired, the method for generating the site information is not limited. The site information generation unit 23 writes the site information to the memory 12.

An example of site information when the biological signal is ECG will be described with reference to FIG.
FIG. 3 shows an example in which ECG waveforms measured at a plurality of locations are superimposed and compared. Specifically, FIG. 3 shows an ECG waveform measured by the wrist and an ECG waveform measured by the palm of the same individual. As shown in FIG. 3, it can be seen that even in the same individual, there is a difference between the maximum value and the time when the maximum value appears. Therefore, it is conceivable to use the maximum value in the ECG waveform and the time when the maximum value appears as site information.

An example of site information when the biological signal is PPG will be described with reference to FIG.
FIG. 4 shows an example in which PPG waveforms measured at a plurality of locations are superimposed and compared. Specifically, FIG. 4 shows a PPG waveform measured by a finger and a PPG waveform measured by a forehead for the same individual. As shown in FIG. 4, it can be seen that even in the same individual, there is a difference between the time when the first maximum value appears and the two maximum values. Therefore, it is conceivable to use the maximum value in the PPG waveform and the time when the maximum value appears as site information.

(Step S104: First authentication process)
The authentication unit 24 compares the authentication information generated in step S102 with the authentication standard information stored in the auxiliary storage device 16 in advance, and determines whether the first authentication is successful or unsuccessful.
Specifically, the authentication unit 24 has the authentication information generated in step S102 and the authentication standard information having a similarity of the first threshold value or more, or the authentication information generated in step S102 and the authentication standard information. It is determined whether or not the condition that the difference between the and is within the allowable value is satisfied. If the condition is satisfied, the authentication unit 24 determines that the first authentication has succeeded, and if the condition is not satisfied, determines that the first authentication has failed.
If it is determined that the first authentication is successful, the authentication unit 24 advances the process to step S105. On the other hand, if it is determined that the first authentication has failed, the authentication unit 24 determines that the authentication has failed and ends the process. If it is determined that the first authentication has failed, the process may be returned to step S101 and the authentication process may be redone.

(Step S105: Second authentication process)
The authentication unit 24 compares the site information generated in step S103 with the site reference information stored in the auxiliary storage device 16 in advance, and determines whether the second authentication succeeds or fails.
Specifically, the authentication unit 24 has the site information generated in step S103 and the site reference information having a similarity of the second threshold value or more, or the site information generated in step S103 and the site reference information. It is determined whether or not the condition that the difference between the and is within the allowable value is satisfied. If the condition is satisfied, the authentication unit 24 determines that the second authentication has succeeded, and if the condition is not satisfied, determines that the second authentication has failed.
If it is determined that the second authentication is successful, the authentication unit 24 considers the authentication successful and ends the process. On the other hand, if it is determined that the second authentication has failed, the authentication unit 24 determines that the authentication has failed and ends the process. If it is determined that the second authentication has failed, the process may be returned to step S101 and the authentication process may be redone.

In step S104, it was explained that the authentication standard information was stored in the auxiliary storage device 16 in advance. Further, in step S105, it was explained that the site reference information was stored in the auxiliary storage device 16 in advance.
As described above, it is necessary to store the authentication standard information and the site standard information as a premise for performing the process shown in FIG. Specifically, the processes from step S101 to step S103 are executed, the authentication information generated in step S102 is stored as authentication reference information, and the site information generated in step S103 is stored as site reference information.
Authentication information and site information may change over the years. Therefore, when a certain period of time has passed, the authentication standard information and the site standard information may be reacquired. Then, as shown in FIG. 5, the authentication reference information and the site reference information are stored together with the measurement date and time of the biological signal for one subject. Note that FIG. 5 shows a case where the feature amount is used as the authentication standard information and the site standard information.

The execution order of step S102 and step S103 and the execution order of step S104 and step S105 are not limited to the order shown in FIG. 2, and may be interchanged.

*** Effect of Embodiment 1 ***
As described above, the authentication device 10 according to the first embodiment authenticates using the site information in addition to the authentication information. As a result, it is possible to control so that authentication does not succeed when a biological signal illegally measured at a site other than the intended site is used. Therefore, it is possible to implement countermeasures against spoofing attacks due to unauthorized measurement of biological signals.

*** Other configurations ***
<Modification 1>
The number of sensors 31 is not particularly limited. Authentication information and site information may be generated from a single biological signal measured by a single sensor, or authentication information and site information may be generated from a plurality of biological signals measured by a plurality of sensors. ..
Further, the signal acquisition unit 21 may control the sensor 31 via the sensor interface 13 to switch between a biological signal for generating authentication information and a biological signal for generating site information. For example, the signal acquisition unit 21 may switch the sensor 31 to be used or change the set value required for the operation of the sensor 31. In this case, the authentication information generation unit 22 generates the authentication information from the biological signal for generating the authentication information, and the site information generation unit 23 generates the site information from the biological signal for generating the site information. ..

<Modification 2>
In the first embodiment, if the first authentication based on the authentication information and the second authentication based on the site information are successful once, the authentication is successful. However, if the first authentication based on the authentication information and the second authentication based on the site information are successful a plurality of times in succession, the authentication may be successful.

With reference to FIG. 6, the flow of processing of the authentication device 10 according to the second modification will be described.
The process from step S111 to step S115 is the same as the process from step S101 to step S105 in FIG. However, in step S115, if it is determined that the second authentication is successful, the authentication unit 24 advances the process to step S116.

(Step S116: Continuation determination process)
The authentication unit 24 determines whether or not the number of successful first and second authentications has reached the reference number of times.
When the number of successes reaches the reference number, the authentication unit 24 considers the authentication to be successful and ends the process. On the other hand, if the number of successes has not reached the reference number, the authentication unit 24 returns the process to step S111.

In the second and subsequent steps S115, the authentication unit 24 may determine whether or not the site information is the site information for the same site as the site information generated for the first time. Then, if the condition is satisfied and the site information is the site information about the same site as the site information generated for the first time, the authentication unit 24 may determine that the second authentication has been successful.
As a result, if the measurement site is changed during the process, the authentication may fail. That is, if the sensor moves in the middle of the process, the authentication may fail.

<Modification 3>
In the first embodiment, each functional component is realized by software. However, as a modification 1, each functional component may be realized by hardware. The difference between the first modification and the first embodiment will be described.

With reference to this, the configuration of the authentication device 10 according to the first modification will be described.
When each functional component is implemented in hardware, the authentication device 10 includes an electronic circuit instead of the processor 11, the memory 12, and the auxiliary storage device 16. The electronic circuit is a dedicated circuit that realizes the functions of each functional component, the memory 12, and the auxiliary storage device 16.

As the electronic circuit, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA (Gate Array), an ASIC (Application Specific Integrated Circuit), and an FPGA (Field-Programmable Gate Array) are assumed. Will be done.
Each functional component may be realized by one electronic circuit, or each functional component may be distributed and realized by a plurality of electronic circuits.

<Modification example 4>
As a modification 4, some functional components may be realized by hardware, and other functional components may be realized by software.

The processor 11, the memory 12, the auxiliary storage device 16, and the electronic circuit are called processing circuits. That is, the function of each functional component is realized by the processing circuit.

Embodiment 2.
The second embodiment is different from the first embodiment in that at least one of authentication information and site information is generated from a composite signal generated by performing an operation by inputting a plurality of biological signals acquired from a plurality of sensors 31. .. In the second embodiment, these different points will be described, and the same points will be omitted.
In the second embodiment, a case where both the authentication information and the site information are generated from the composite signal will be described.

*** Explanation of configuration ***
The configuration of the authentication device 10 according to the second embodiment will be described with reference to FIG. 7.
The authentication device 10 differs from the authentication device 10 shown in FIG. 1 in that the authentication device 10 includes a signal calculation unit 25 as a functional component. The signal calculation unit 25 is realized by software or hardware like other functional components.
Further, the authentication device 10 is different from the authentication device 10 shown in FIG. 1 in that the processor 11 is connected to a plurality of sensors 31 via the sensor interface 13. Each sensor 31 may be a sensor having the same specifications or may be a sensor having different specifications.

*** Explanation of operation ***
The operation of the authentication device 10 according to the second embodiment will be described with reference to FIGS. 8 and 9.
The operation procedure of the authentication device 10 according to the second embodiment corresponds to the authentication method according to the second embodiment. Further, the program that realizes the operation of the authentication device 10 according to the second embodiment corresponds to the authentication program according to the second embodiment.

With reference to FIG. 8, the flow of processing of the authentication device 10 according to the second embodiment will be described.
The process from step S206 to step S207 is the same as the process from step S104 to step S105 in FIG.

(Step S201: Calculation method determination process)
The signal calculation unit 25 determines a calculation method for calculating a composite signal. As a specific example, the calculation method is addition or subtraction of a plurality of biological signals. However, the calculation method is not limited to this.
Specifically, the signal calculation unit 25 determines the calculation method by a method such as accepting a designation of the calculation method from a target person or the like and reading a preset calculation method.

(Step S202: Signal acquisition process)
The signal acquisition unit 21 acquires a plurality of biological signals of the subject from the plurality of sensors 31 connected via the sensor interface 13. The signal acquisition unit 21 writes a plurality of biological signals to the memory 12.

(Step S203: Signal calculation processing)
The signal calculation unit 25 receives a plurality of biological signals acquired in step S202 as inputs, performs calculations by the calculation method determined in step S201, and generates a composite signal. The signal calculation unit 25 writes the composite signal to the memory 12.

An example of a composite signal will be described with reference to FIG.
FIG. 9 shows an example in which PPG is measured by two sensors 31 and the obtained PPGs are calculated with each other. PPG is measured by irradiating a blood vessel with light from a light source and acquiring reflected light or transmitted light obtained by a light receiving unit. The waveform of PPG is different depending on the wavelength (color) of the light source. In particular, the depth at which light can reach in a living body differs depending on the wavelength. Therefore, for example, as shown in FIG. 9, it is considered that only deep information can be extracted by calculating the difference between the biological signal obtained by green light and the biological signal obtained by infrared light. It is considered that the composite signal obtained by the calculation between each biological signal is more difficult to artificially generate than the single biological signal.

(Step S204: Authentication information generation process)
The authentication information generation unit 22 generates authentication information from the composite signal generated in step S203. The method of generating the authentication information is the same as that of the first embodiment except that a composite signal is input instead of the biological signal. The authentication information generation unit 22 writes the authentication information in the memory 12.

(Step S205: Part information generation process)
The site information generation unit 23 generates site information from the composite signal generated in step S203. The method of generating the site information is the same as that of the first embodiment except that a composite signal is input instead of the biological signal. The site information generation unit 23 writes the site information to the memory 12.

As a prerequisite for performing the process shown in FIG. 8, it is necessary to store the authentication standard information and the site standard information. Specifically, the processes from step S201 to step S205 are executed, the authentication information generated in step S204 is stored as authentication reference information, and the site information generated in step S205 is stored as site reference information. Similar to the first embodiment, the certification standard information and the site standard information may be reacquired after a certain period of time has passed.

The execution order of step S204 and step S205 and the execution order of step S206 and step S207 are not limited to the order shown in FIG. 2, and may be interchanged.

*** Effect of Embodiment 2 ***
As described above, the authentication device 10 according to the second embodiment generates at least one of authentication information and site information from a composite signal obtained by calculation from a plurality of biological signals. Composite signals are considered to be more difficult to artificially generate than single biological signals. Therefore, it is possible to realize better countermeasures against spoofing attacks due to illegal measurement of biological signals.

*** Other configurations ***
<Modification 5>
Similar to the second modification, if the first authentication based on the authentication information and the second authentication based on the site information are successful a plurality of times in succession, the authentication may be successful.

With reference to FIG. 10, the processing flow of the authentication device 10 according to the modified example 5 will be described.
The process from step S211 to step S217 is the same as the process from step S201 to step S207 in FIG. However, in step S207, if it is determined that the second authentication is successful, the authentication unit 24 advances the process to step S218.

(Step S218: Continuation determination process)
The authentication unit 24 determines whether or not the number of successful first and second authentications has reached the reference number of times.
When the number of successes reaches the reference number, the authentication unit 24 considers the authentication to be successful and ends the process. On the other hand, if the number of successes has not reached the reference number, the authentication unit 24 returns the process to step S211.

In addition, as in the modification 2, in the second and subsequent steps S217, the authentication unit 24 may determine whether or not the site information is the site information for the same site as the site information generated for the first time. good. Then, if the condition is satisfied and the site information is the site information about the same site as the site information generated for the first time, the authentication unit 24 may determine that the second authentication has been successful.
Further, in step S211 the calculation method may be changed each time so as not to be observed by an attacker, and a composite signal may be generated by a different calculation method each time. This makes it possible to further increase the difficulty of spoofing attacks.

Embodiment 3.
The third embodiment is different from the first embodiment in that the biological signal corresponding to the sensor control information is acquired by giving the sensor control information to the sensor 31 and then acquiring the biological signal. In the third embodiment, these different points will be described, and the same points will be omitted.

*** Explanation of configuration ***
The configuration of the authentication device 10 according to the third embodiment will be described with reference to FIG.
The authentication device 10 differs from the authentication device 10 shown in FIG. 1 in that the processor 11 is connected to a plurality of sensors 31 via the sensor interface 13. Each sensor 31 is controlled by the sensor control information given from the processor 11.
Although the case where a plurality of sensors 31 are used will be described here, the authentication device 10 may use a single sensor 31 to acquire different biological signals according to the sensor control information.

*** Explanation of operation ***
The operation of the authentication device 10 according to the third embodiment will be described with reference to FIGS. 12 and 14.
The operation procedure of the authentication device 10 according to the third embodiment corresponds to the authentication method according to the third embodiment. Further, the program that realizes the operation of the authentication device 10 according to the third embodiment corresponds to the authentication program according to the third embodiment.

With reference to FIG. 12, the processing flow of the authentication device 10 according to the third embodiment will be described.
The process from step S303 to step S304 is the same as the process from step S102 to step S103 in FIG.

(Step S301: Control information determination process)
The signal acquisition unit 21 determines the sensor control information. As a specific example, the sensor control information is information indicating which sensor 31 is used among the plurality of sensors 31, and setting information of the wavelength (color) of the light source included in the optical sensor. However, the sensor control information is not limited to this.
Specifically, the signal acquisition unit 21 determines the sensor control information by a method of accepting the designation of the sensor control information from the target person or the like and reading out the preset sensor control information. As a method of setting in advance, it is conceivable to determine the sensor control information to be used according to the time. For example, a method of deciding to use a green light source before time t1 and to use an infrared light source after time t1 can be considered. In addition, it is conceivable to randomly determine the order of use of control information in advance. For example, a method of deciding to use a green light source and a red light source alternately can be considered.

(Step S302: Signal acquisition process)
The signal acquisition unit 21 acquires a biological signal corresponding to the sensor control information determined in step S301 from the sensor 31 connected via the sensor interface 13.
Specifically, the signal acquisition unit 21 controls the sensor 31 by the sensor control information determined in step S301, and then acquires the biological signal from the sensor 31. The signal acquisition unit 21 writes the biological signal to the memory 12.

(Step S305: First authentication process)
The authentication unit 24 performs the first authentication using the standard according to the sensor control information determined in step S301.
Specifically, the authentication unit 24 compares the authentication information generated in step S303 with the authentication standard information stored in the auxiliary storage device 16 in advance and corresponding to the sensor control information. Then, it is determined whether the first authentication is successful or unsuccessful. At this time, the authentication unit 24 determines whether or not the first authentication is successful or unsuccessful by determining whether or not the conditions corresponding to the sensor control information are satisfied.
If it is determined that the first authentication is successful, the authentication unit 24 advances the process to step S306. On the other hand, if it is determined that the first authentication has failed, the authentication unit 24 determines that the authentication has failed and ends the process. If it is determined that the first authentication has failed, the process may be returned to step S301 and the authentication process may be redone.

(Step S306: Second authentication process)
The authentication unit 24 performs the second authentication using the standard according to the sensor control information determined in step S301.
Specifically, the authentication unit 24 compares the site information generated in step S304 with the site reference information stored in the auxiliary storage device 16 in advance and corresponding to the sensor control information. Then, it is determined whether the second authentication is successful or unsuccessful. At this time, the authentication unit 24 determines whether the second authentication is successful or unsuccessful by determining whether or not the conditions corresponding to the sensor control information are satisfied.
If it is determined that the second authentication is successful, the authentication unit 24 considers the authentication successful and ends the process. On the other hand, if it is determined that the second authentication has failed, the authentication unit 24 determines that the authentication has failed and ends the process. If it is determined that the second authentication has failed, the process may be returned to step S301 and the authentication process may be redone.

As a premise for performing the process shown in FIG. 12, it is necessary to store the authentication standard information and the site standard information corresponding to the sensor control information. Specifically, the processes from step S301 to step S304 are executed, the authentication information generated in step S303 is stored as authentication reference information, and the site information generated in step S304 is stored as site reference information. At this time, the processes from step S301 to step S304 are executed for each sensor control information used, and the authentication reference information and the site reference information corresponding to each sensor control information are stored.
As a result, as shown in FIGS. 13 and 14, authentication reference information and site reference information are stored together with the measurement date and time of the biological signal for each sensor control information for one subject. FIG. 13 shows an example in which the sensor 31 to be used is changed according to the sensor control information. FIG. 14 shows an example in which the light source is changed according to the sensor control information. Note that FIGS. 13 and 14 show a case where the feature amount is used as the authentication standard information and the site reference information. In FIG. 13, the authentication standard information and the site reference information when the sensor 1 is used and when the sensor 2 is used are stored for each target person. In FIG. 14, the authentication standard information and the site standard information when the light source is green and when the light source is red are stored for each target person.

The execution order of step S303 and step S304 and the execution order of step S305 and step S306 are not limited to the order shown in FIG. 2, and may be interchanged.

*** Effect of Embodiment 3 ***
As described above, the authentication device 10 according to the third embodiment acquires a biological signal corresponding to the sensor control information. For example, PPG is measured by using a light source such as green and infrared light together with a photodetector, but the waveform measured by the wavelength of the light source is different. Therefore, by changing the wavelength of the light source, different information can be obtained as authentication information and site information. Sensor control information cannot be observed from the attacker. For example, an attacker cannot observe the type of light source used as control information or the sensor 31 used. Therefore, spoofing attacks by measuring or generating biological signals used for authentication are impossible, or the difficulty level is higher than in the case of the first embodiment.

*** Other configurations ***
<Modification 6>
Similar to the second modification, if the first authentication based on the authentication information and the second authentication based on the site information are successful a plurality of times in succession, the authentication may be successful.

A flow of processing of the authentication device 10 according to the modification 6 will be described with reference to FIG.
The process from step S311 to step S316 is the same as the process from step S301 to step S306 in FIG. However, in step S306, if it is determined that the second authentication is successful, the authentication unit 24 advances the process to step S317.

(Step S317: Continuation determination process)
The authentication unit 24 determines whether or not the number of successful first and second authentications has reached the reference number of times.
When the number of successes reaches the reference number, the authentication unit 24 considers the authentication to be successful and ends the process. On the other hand, if the number of successes has not reached the reference number, the authentication unit 24 returns the process to step S311.

In addition, as in the modification 2, in the second and subsequent steps S316, the authentication unit 24 may determine whether or not the site information is the site information for the same site as the site information generated for the first time. good. Then, if the condition is satisfied and the site information is the site information about the same site as the site information generated for the first time, the authentication unit 24 may determine that the second authentication has been successful.
Further, in step S311, the sensor control information may be changed each time. This makes it possible to further increase the difficulty of spoofing attacks.

Embodiment 4.
The fourth embodiment differs from the first embodiment in that authentication is performed using physiological indicators such as heart rate and respiratory rate, which are specified by using a plurality of methods such as an optical method and an electrical method. The fourth embodiment explains these different points, and omits the description of the same points.

*** Explanation of configuration ***
The configuration of the authentication device 10 according to the fourth embodiment will be described with reference to FIG.
The authentication device 10 differs from the authentication device 10 shown in FIG. 1 in that the authentication device 10 includes a physiological index generation unit 26 as a functional component. The physiological index generation unit 26 is realized by software or hardware like other functional components.
Further, the authentication device 10 is different from the authentication device 10 shown in FIG. 1 in that the processor 11 is connected to a plurality of sensors 31 via the sensor interface 13. As the plurality of sensors 31, sensors that measure different physical quantities, such as an optical sensor and a vibration sensor, are used.

*** Explanation of operation ***
The operation of the authentication device 10 according to the fourth embodiment will be described with reference to FIGS. 17 to 19.
The operation procedure of the authentication device 10 according to the fourth embodiment corresponds to the authentication method according to the fourth embodiment. Further, the program that realizes the operation of the authentication device 10 according to the fourth embodiment corresponds to the authentication program according to the fourth embodiment.

A flow of processing of the authentication device 10 according to the fourth embodiment will be described with reference to FIG.
The process from step S402 to step S403 is the same as the process from step S102 to step S103 in FIG. The process from step S405 to step S406 is the same as the process from step S104 to step S105 in FIG. However, in step S406, if it is determined that the second authentication is successful, the process proceeds to step S407 instead of making the authentication successful.

(Step S401: Signal acquisition process)
The signal acquisition unit 21 acquires a plurality of biological signals of the subject from the plurality of sensors 31 connected via the sensor interface 13. The signal acquisition unit 21 writes a plurality of biological signals to the memory 12.

Here, a plurality of biological signals are acquired, but in step S402, the authentication information may be generated from any one biological signal, or the authentication information may be generated from a plurality of biological signals. Similarly, in step S403, the site information may be generated from any one biological signal, or the site information may be generated from a plurality of biological signals. In addition, authentication information and site information may be generated by using another biological signal.

(Step S404: Physiological index generation process)
The physiological index generation unit 26 generates a physiological index related to the same physiology from each of the plurality of biological signals acquired in step S401. The physiological index generation unit 26 writes the physiological index generated from each biological signal into the memory 12.

An example of a physiological index will be described with reference to FIG.
In FIG. 18, the PPG of the subject is measured by the PPG measurement sensor, and the minute vibration of the subject is measured by a vibration measurement sensor such as a piezoelectric element. It is known that physiological indexes such as heart rate and respiratory rate can be obtained from PPG. It is known that physiological indexes such as heart rate and respiratory rate can be obtained from minute vibrations obtained by a vibration measurement sensor. Therefore, it is conceivable that the physiological index generation unit 26 generates the heart rate as a physiological index from each of PPG and minute vibration, for example.

(Step S407: Third authentication process)
The authentication unit 24 compares the physiological indexes generated from each of the plurality of biological signals, and determines whether the third authentication is successful or unsuccessful.
Specifically, in the authentication unit 24, the similarity of the physiological indicators generated from each of the plurality of biological signals is equal to or higher than the third threshold value, or the difference between the physiological indicators generated from each of the plurality of biological signals is an allowable value. It is determined whether or not the condition such as within is satisfied. If the condition is satisfied, the authentication unit 24 determines that the third authentication has succeeded, and if the condition is not satisfied, determines that the third authentication has failed.
If it is determined that the third authentication is successful, the authentication unit 24 considers the authentication successful and ends the process. On the other hand, if it is determined that the third authentication has failed, the authentication unit 24 determines that the authentication has failed and ends the process. If it is determined that the third authentication has failed, the process may be returned to step S401 and the authentication process may be redone.

In addition, as a condition for determining whether the third authentication succeeds or fails, a condition such as whether the difference between the physiological index generated from each of a plurality of biological signals and the reference value of the physiological index is within the allowable value is included. You may. In this case, as shown in FIG. 19, it is necessary to store the reference value of the physiological index in addition to the authentication reference information and the site reference information as a premise for performing the process shown in FIG. Specifically, the processes from step S401 to step S404 are executed, and the average value or the like of the physiological index generated in step S404 is stored as the reference value of the physiological index.

The execution order from step S402 to step S404 and the execution order from step S405 to step S407 are not limited to the order shown in FIG. 17, and may be interchanged.

*** Effect of Embodiment 4 ***
As described above, the authentication device 10 according to the fourth embodiment performs authentication using a physiological index in addition to the authentication information and the site information. This makes it possible to guarantee to some extent that the object to be measured is a living body. Further, since different physical quantities are measured by the plurality of sensors 31, the labor and difficulty of artificial signal generation become high, and as a result, the difficulty of spoofing attack becomes high.

*** Other configurations ***
<Modification 7>
Similar to the second modification, if the first authentication based on the authentication information, the second authentication based on the site information, and the third authentication based on the physiological index are successful a plurality of times in succession, the authentication may be successful. ..

With reference to FIG. 20, the flow of processing of the authentication device 10 according to the modification 7 will be described.
The process from step S411 to step S417 is the same as the process from step S401 to step S407 in FIG. However, in step S407, if it is determined that the third authentication is successful, the authentication unit 24 proceeds to step S418.

(Step S418: Continuation determination process)
The authentication unit 24 determines whether or not the number of successes of the first authentication, the second authentication, and the third authentication has reached the reference number of times.
When the number of successes reaches the reference number, the authentication unit 24 considers the authentication to be successful and ends the process. On the other hand, if the number of successes has not reached the reference number, the authentication unit 24 returns the process to step S411.

In addition, as in the modification 2, in the second and subsequent steps S416, the authentication unit 24 may determine whether or not the site information is the site information for the same site as the site information generated for the first time. good. Then, if the condition is satisfied and the site information is the site information about the same site as the site information generated for the first time, the authentication unit 24 may determine that the second authentication has been successful.

Note that the "part" in the above description may be read as "circuit", "process", "procedure", "processing" or "processing circuit".

The embodiments and modifications of the present disclosure have been described above. Some of these embodiments and modifications may be combined and carried out. In addition, any one or several may be partially carried out. The present disclosure is not limited to the above embodiments and modifications, and various modifications can be made as necessary.

10 authentication device, 11 processor, 12 memory, 13 sensor interface, 14 display interface, 15 communication interface, 16 auxiliary storage device, 21 signal acquisition unit, 22 authentication information generation unit, 23 part information generation unit, 24 authentication unit, 25 Signal calculation unit, 26 physiological index generation unit, 31 sensor.

Claims

A signal acquisition unit that acquires biological signals,
An authentication information generation unit that generates different authentication information according to an individual living body from the biological signal acquired by the signal acquisition unit.
A site information generation unit that generates different site information from the biological signal depending on the acquisition site of the biological signal.
An authentication device including an authentication unit that performs authentication based on the authentication information generated by the authentication information generation unit and the site information generated by the site information generation unit.
The authentication device according to claim 1, wherein the authentication unit determines whether or not the authentication is successful, depending on whether or not the authentication information satisfies the standard and the site information satisfies the standard.
The signal acquisition unit acquires the biological signal a plurality of times at different times.
The site information generation unit generates the site information for each of the biological signals acquired a plurality of times.
According to claim 2, the authentication unit determines whether or not the authentication is successful, depending on whether or not the site information for each of the biological signals acquired a plurality of times is site information for the same site. Authentication device.
The signal acquisition unit acquires a plurality of biological signals and obtains them.
The authentication device further
It is provided with a signal calculation unit that performs calculations using the plurality of biological signals as inputs and generates a composite signal.
The authentication device according to claim 1 or 2, wherein the authentication information generation unit generates the authentication information from the composite signal generated by the signal calculation unit.
The signal acquisition unit acquires a plurality of biological signals and obtains them.
The authentication device further
It is provided with a signal calculation unit that performs calculations using the plurality of biological signals as inputs and generates a composite signal.
The authentication device according to claim 1 or 2, wherein the site information generation unit generates the site information from the composite signal generated by the signal calculation unit.
The signal acquisition unit acquires a plurality of biological signals at different times and multiple times.
The authentication device according to claim 4 or 5, wherein the signal calculation unit calculates the plurality of biological signals acquired a plurality of times by different calculation methods to generate the composite signal.
The signal acquisition unit acquires a biological signal according to the sensor control information, and obtains a biological signal.
The authentication device according to any one of claims 1 to 6, wherein the authentication unit performs authentication based on the authentication information and the site information using a standard according to the sensor control information.
The signal acquisition unit acquires biological signals corresponding to sensor control information that are different for each time, at different times, a plurality of times.
The authentication unit uses each of the biometric signals acquired a plurality of times as the biometric signal of the target, and uses the reference corresponding to the sensor control information corresponding to the biometric signal of the target to obtain the authentication information of the biometric signal of the target. The authentication device according to claim 7, wherein the authentication is performed based on the site information.
The signal acquisition unit acquires a plurality of biological signals and obtains them.
The authentication device further
It is provided with a physiological index generation unit that generates a physiological index related to the same physiology from each of the plurality of biological signals.
The authentication device according to any one of claims 1 to 8, wherein the authentication unit compares the physiological indexes generated from each of the plurality of biological signals by the physiological index generation unit, and performs authentication.
The signal acquisition unit acquires the biological signal and
The authentication information generation unit generates different authentication information from the biological signal according to the individual of the living body.
The site information generation unit generates different site information from the biological signal according to the acquisition site of the biological signal.
An authentication method in which an authentication unit performs authentication based on the authentication information and the site information.
Signal acquisition processing to acquire biological signals and
Authentication information generation processing that generates authentication information that differs depending on the individual of the living body from the biological signal acquired by the signal acquisition processing, and
A site information generation process that generates different site information from the biological signal depending on the site where the biological signal is acquired.
An authentication program that causes a computer to function as an authentication device that performs an authentication process for performing authentication based on the authentication information generated by the authentication information generation process and the site information generated by the site information generation process.